The way I read the provided information, there was no real intention for the thing to be green.
Doing a post analysis in this way, is an unnecessary splitting of hairs. It's like "proving water is wet". Who knew?
That ship has sailed -- in a sense.
The inclusion of dual fuels, is a practical matter regarding fuel availability in the current day. To make the thing dependent on fossil fuels, I don't see how the thing could end up with "religious purity" as a result.
*******And that was done by Wärtsilä as well, the same company that did the power train for the Glen Sannox.
Paul